NO. 4 AVIAN GENUS CLAMATOR — FRIEDMANN 37 



started with, and has not deviated from, a fixation upon a single- 

 host species, its close and antecedent relative, the bay-winged cow- 

 bird, M. badius. Furthermore, the parasitic Viduinae are still in the 

 original stage of limited range of hosts, their Estrildine relatives, the 

 waxbills. It also seems not improbable that the great-spotted cuckoo, 

 Clamator glandariiis, early became involved with, and went through 

 its eggshell evolution with a single host, the magpie. Pica pica; the 

 same is true of the stripe-breasted cuckoo, Clamator levaillantii, with 

 its chief host, the babbler, Turdoides jardinei, and of the koel, 

 Eudynamis scolopacea, with its use of crows. The evolution of 

 host egg similarity obviously is facilitated by species-host specificity. 



INTENSITY OF PARASITISM 



By intensity of parasitism two quite separate things are implied. 

 The percentage of the total nests of frequently used hosts that are 

 parasitized gives one aspect of the parasite-host situation. The fre- 

 quency with which individual parasitized nests are found to contain 

 more than one egg of the cuckoo adds still another element of the 

 total picture. On the whole, increase in frequency of multiple-egg 

 parasitism on the same pair of hosts is something that is super- 

 imposed on the basic situation. While in some areas where the host 

 nests are very numerous the incidence of multiple parasitism appears 

 to be lower than in places where there are relatively few hosts for 

 the number of cuckoos, this cannot yet be demonstrated convincingly, 

 as in no area have the data been sufficiently extensive and intensive 

 to give a precise survey of the numerical status of the hosts and of 

 the parasite, or of the percent of nests of the favorite fosterers that 

 are parasitized. Perhaps the nearest approximation to the kind of 

 information needed is that afforded by Mountfort (1958, p. 54). In 

 his fieldwork in Spain, he examined 7 nests of the magpie on one 

 afternoon and found that 5 of them were parasitized by the great- 

 spotted cuckoo, an incidence of simultaneous parasitism of 71.4 per- 

 cent in a circumscribed area. Mountfort did not list the numbers of 

 eggs or of young of either the host or the parasite in each of these 

 nests, so his observations tell us something of the percent of magpie 

 nests parasitized but not how intensively they had been affected. 

 However, a compilation of all the cases he mentioned shows that of 

 eight parasitized nests, none were found to have only a single cuckoo 

 egg apiece. His figures are quite different from those given below 

 for 28 other parasitized magpie nests, all also from Spain. Mountfort 

 found some 50 occupied magpie nests in that country in 1956, but 



